The present invention relates generally to dry and wet mateable underwater connectors, and is particularly concerned with an improved underwater seal assembly for the pin/socket junction elements of fiber-optical and electrical connectors which seals against pressure while permitting compliance of the optical junctions.
There are presently on the market connectors for simultaneously joining multiple electrical and/or fiber-optical circuits in a dry environment with subsequent immersion to great ocean depths. There are similar connectors which, when pre-treated with a bit of optical matching gel, which may also act as a dielectric, can be successfully mated once or at most a few times underwater. All of the connectors of these sorts have the challenge that they must seal against high pressures while providing low-loss optical transmission.
The challenge has, until now, not been adequately answered. The problem has been that the same traditional sealing techniques that render the assemblies pressure proof also cause them to rigidly grasp the pin and socket elements that are housed within them. To achieve low-loss optical junctions, the contacting elements within the connectors must be free to adjust geometrically to each other such that their cores, through which light is transmitted, are precisely aligned. Each pin/socket generally has an individual alignment device that is independent on a small scale from the alignment of the overall connector housings. That is, gross alignment of the elements is achieved by the relative positions of the housings. But final alignment of the contacts must take place locally at each individual pin/socket junction. If that final alignment is inhibited, as it is in current products on the market, by the pin/socket sealing means, then imperfect alignment with concomitant poor light transmission will result. The present invention addresses and solves this problem through the employment of low-stress gland seals that permit compliant mounting of the pin/socket elements while sealing against high pressure.
A typical underwater connector for sealably connecting a plurality of fiber-optical and/or electrical circuits comprises a plug unit and a receptacle unit which are releasably securable together either on land prior to submerging the connector, or, in a slightly changed form, underwater.
The plug unit typically contains a plurality of contact probes or pins to which fiber-optic or electrical leads are terminated. The receptacle unit contains a corresponding number of sockets into whose terminal ends a corresponding number of fiber-optic or electrical leads are terminated. The probes or pins are mated with the sockets when the two units are coupled together. As the plug and receptacle are coupled together, the contact pins must mate with the respective sockets. The optical circuits of such connectors, until now, have been of limited use due to the fact that their mounting means have not been compliant enough to permit reliable low-loss junctions. Optical pins and sockets in such underwater connectors require sealing against high pressures, and have been fixed into bores to which they seal with O-rings. The result is a rather non-compliant assembly. But compliance is required on at least one side, pin or socket, for low optical loss: It allows each pin/socket junction to self align. The difficult problem, until now, has been to simultaneously provide adequate compliance and sealing against high pressure.